Subletting Issue

8 months ago, I rented a condo in Mississisauga and signed a one year lease, but due to a change of work, I need to move to Toronto at month 8. I then asked the landlord if I can sublease the place due to my personal reason, and acquired his consent. In April, I found another guy who was willing to take my lease (the last four months) so I sent his info to the landlord for his approval. He then approved it and upon his confirmation, I signed another new lease in Toronto for a year and I moved in. However, when the new tenant was trying to move in my landlord's property, the property management in that building stopped him and stated according to building rules, no sublease is allowed.

My landlord tried to negotiate but it didn't change anything. I can't move back as well because I am currently stuck in another lease. The new tenant will be kicked out from his current place in 2 days and I have taken the responsibility to accommodate him and paid for temporarily storage for his furniture.

By the time my landlord signed the lease with me, he collected the first month and last 4 months rent so now he's paid for the full year while I am not able to live anymore in his condo and I called to ask for the money back and he refused.

Am I really obliged to pay for that four months I will not be living in his property?? Please help me.